Method for producing a color accurate proof of a printed product

Abstract

In this method, a surface of a digital master of the printed product is subdivided into a plurality of areas based on at least a first area of the printed product being printed having a first set of color-affecting printing characteristics and at least a second area of the printed product having a second set of color-affecting printing characteristics. Each of the plurality of areas are assigned a printing press color profile or device link, and the colors from colorspaces corresponding to each set of color-affective printing characteristics are converted to a colorspace of the proofing device. This conversion is accomplished by determining, for each pixel, one of the plurality of areas of the digital master surface that the pixel belongs to, selecting the color profile or the device link profile, converting the values to proof colorant values, and assigning the proof colorant values to the proof.

What is claimed is: 
     
         1 . A method to produce a color accurate proof of a printed product, comprising:
 (a) subdividing, by a host computer, a surface of a digital master of the printed product into a plurality of areas based on at least a first area of the printed product being printed having a first set of color-affecting printing characteristics and at least a second area of the printed product having a second set of color-affecting printing characteristics;   (b) assigning, by the host computer, each of the plurality of areas a printing press color profile or device link based on the respective set of color-affecting printing characteristics corresponding to the respective area; and   (c) converting, by the host computer, colors from colorspaces corresponding to each set of color-affective printing characteristics to a colorspace of a proofing device by:
 (i) determining, for each pixel at location (x, y) at least one of the plurality of areas of the digital master surface that the pixel belongs to, where x and y are variables defining a two dimensional space of the digital master, 
 (ii) selecting the color profile or the device link profile assigned to each of the determined areas, resulting in a list of color profiles or device links, 
 (iii) converting final print color-affecting values to proofing device colorant values using the list of printing press profiles or device links, and 
 (iv) assigning the proofing device colorant values to the pixel (x′, y′) of the proof that corresponds with location (x, y) of the digital master surface. 
   
     
     
         2 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface so that the areas are non-overlapping and each area includes one printing press profile or device link.   
     
     
         3 . The method in  claim 1 , including:
 converting, by the host computer, the printing press colorants to proofing device colorants by:   converting, by the host computer, the set of color-affecting printing characteristics to proofing device colorants for each printing press profile or device link in the list, and   combining, by the host computer, the proofing device colorants to mimic the final print color-affecting values using a blending algorithm.   
     
     
         4 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface of the digital master in areas using data embedded in a portable document format (PDF) file.   
     
     
         5 . The method in  claim 4 , including:
 using, by the host computer, PDF file objects that are colored using spot colors with specified names to subdivide the surface of the digital master.   
     
     
         6 . The method in  claim 5 , including:
 using, by the host computer, the PDF file objects that are member of optional content groups with specific names to subdivide the surface of the digital master   
     
     
         7 . The method in  claim 5 , including:
 using, by the host computer, the PDF file objects that are member of optional content groups with specific metadata in the OCG dictionary to subdivide the surface of the digital master   
     
     
         8 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface of the digital master in areas using data external to the PDF file.   
     
     
         9 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface of the digital master of the printed product into the plurality of areas based on:
 the first set of color-affecting printing characteristics corresponding to a first printing device using the first printing process to print ink on at least a first one of the areas of the product identifier using the first printing press color profile or device link, and 
 the second set of color-affecting printing characteristics corresponding to a second printing device configured to perform a second printing process to print ink on at least a second one of the areas of the product identifier different than the first one of the areas using the second printing press color profile or device link. 
   
     
     
         10 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface of the digital master of the printed product into the plurality of areas based on:
 the first set of color-affecting characteristics comprising a first printing process to print color ink on at least a first one of the areas of the product, and 
 the second set of color-affecting characteristics comprising printing a varnish layer on the first one of the areas of the product identifier over the color ink. 
   
     
     
         11 . The method in  claim 1 , including:
 subdividing, by the host computer, the surface of the digital master of the printed product into the plurality of areas based on:
 the first set of color-affecting printing characteristics comprising a first printing process printing color ink on at least a first one of the areas of the product using the first printing press color profile or device link, including printing white ink on at least a second one of the areas of the product, and 
 the second set of color-affecting printing characteristics comprising a second printing process comprising printing color ink on at least the second one of the areas of the product identifier over the white ink as characterized by the second printing press color profile or device link.